This invention relates generally to medical devices and more particularly to an improved trocar assembly to be used in surgical procedures. The trocar includes an improved piercing tip and extendable protector for facilitating the safe and efficient percutaneous entry of the trocar into the body of a human or animal patient. An indicator displays when the protector is in place.
Traditionally, a sharp trocar instrument has been employed to produce an incision in a patient, which is then often followed by the insertion of a cannula to provide an orifice through which necessary drainage or surgical techniques could be performed. One of the major concerns in introducing a trocar into a patient is that the force of incision often produces a considerable follow-through force which may result in accidental puncture wounds to internal organs.
As a result of this concern, a variety of new apparatus have been introduced to attempt to improve upon this basic procedure. One of the major areas of interest has been in attempting to provide an automatic safety shield to surround and protect the trocar tip immediately upon entry into the patient. Examples of such devices are illustrated in, U.S. Pat. No. 4,535,773 issued Aug. 29, 1985 to Yoon, U.S. Pat. No. 4,601,710 issued Jul. 22, 1986 to Moll, U.S. Pat. No. 4,654,030 issued Mar. 31, 1987 to Moll et al., U.S. Pat. No. 4,902,280 issued Feb. 20, 1990 to Lander, U.S. Pat. No. 4,931,042 issued Jun. 6, 1990 to Holmes et al., and U.S. Pat. No. 5,066,288 issued Nov. 19, 1991 to Deniega et al. Although these existing devices improve over previous trocar apparatus, they continue to be plagued with a number of problems.
A concern with the present safety-shielded trocar devices is that the shields do not activate soon enough. In many commercially available shielded trocars, the safety shield comprises essentially a tubular unit which is activated to surround the entire outside of the trocar""s piercing end upon insertion. Examples of such designs are illustrated in each of the above patents. Even though such shields are generally effective at guarding the trocar""s cutting tip, when these units are inserted through the patient""s skin tissue, the tissue surrounding the external safety shield offers significant resistance and impedes shield activation. As a result, the entire piercing end of the trocar and the shield normally must be fully inserted before the shield can activate. If extreme care is not exercised, the incision force often may follow through to cause serious internal injury in the instant before the safety shield can achieve a fully extended position.
The use of an external trocar safety shield also tends to present a myriad of other problems. First, the external shield tends to provide an additional impediment to insertion, thus requiring greater incision force and compounding the risk of follow-through injury. Second, the force of the safety shield passing through the skin tissue often results in tearing and other damage at the incision. In addition to needlessly increasing the size of the surgical wound, this also tends to compromise the foundation of the cannula and may lead to undesirable leaks of fluids and gases during the operation. Third, a number of physicians have complained that the recoil from the xe2x80x9csnappingxe2x80x9d of the safety shield into position at almost the same moment as the trocar insertion tends to disorient them as to the precise location of the trocar after insertion. This results in wasted time and effort to re-orient the trocar and greater risk of internal damage during the period of re-orientation.
Another problem with existing trocar devices is that many employ complicated actuation and locking mechanisms requiring far too much expense and often necessitating costly mated trocar and cannula assemblies. This undermines attempts to recycle those elements (e.g. the cannula) which normally could be sterilized and reused.
In U.S. Pat. No. 5,246,425, issued Sep. 21, 1993 to Hunsberger et al., there is disclosed a trocar assembly for use in creating an incision in a patient which overcomes numerous disadvantages of the prior art listed above. Here, a trocar includes a shaped piercing member with a multitude of cutting edges in a three-dimensional pattern. An internal tip protector is disclosed to protect the patient and medical personnel from accidental puncture injuries by the piercing tip. The tip protector is arranged to become fully extended immediately after the leading edge of the trocar tip enters the patient, e.g., through the skin adjacent an insufflated abdomen, thus avoiding many of the operational drawbacks of existing trocar tip protector designs. The trocar also includes a simple and reliable locking mechanism. However, there is still a need for superior incision capability that provides an ideal cut without tearing of surrounding muscle and tissue and seals well to the trocar.
Additionally, another feature lacking in the prior art that has been found to be of great importance is the ability to visually determine the position of the tip protector as to whether it is fully extended or fully retracted without having to visually see the trocar blade itself. It would be desirable that such an indicator would be visible from the proximal end of the trocar assembly such that as the piercing blade enters the body cavity, the indicator signals that the blade is protected by the tip protector.
Accordingly, it is a general object of the present invention to provide an improved trocar assembly which includes a piercing tip which is effective for piercing through tissue of a patient without tearing the tissue.
It is a further object of the present invention to provide an improved trocar assembly which includes a protective shield which covers the trocar piercing tip upon passage of the tip into the desired region of the patient""s body, e.g., an insufflated abdomen, thereby protecting the patient from injury caused by the tip.
It is a still further object of the present invention to provide an improved trocar assembly which includes a blade position indicator to indicate to a surgeon when the protective shield is in position to protect the trocar blade.
It is another object of the present invention to provide an improved trocar assembly which provides for an incision having a better seal with the trocar such that gases and liquids are less likely to escape from the body cavity during surgical procedures.
It is yet another object of the present invention to provide an improved trocar assembly which permits use with different cannula systems.
Other objects and many attendant features of this invention will become readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings.
The present invention provides an improved trocar assembly for use in a wide variety of surgical procedures on either human or animal patients and is intended for use with a cannula for guarding against accidental puncture wounds of a patient or medical personnel when extended percutaneously into a cavity, e.g., the peritoneal cavity, of the body of a patient. There are three novel aspects of the present invention: the piercing blade in combination with a tapered trocar body near the piercing blade, a trocar tip protector assembly and a tip protector indicator to indicate the position of the trocar tip protector.
The trocar assembly includes a shank having a distal end and a proximal end and a planar piercing blade having two opposed, substantially flat faces, two opposed side edges, and a cutting contour between the opposed side edges. The piercing blade is integrally attached to the distal end of the shank. The cutting edge has a profile to enable it to freely cut through skin and underlying tissue. The shank tapers inwardly towards said opposed flat faces edges of said piercing blade.
The trocar tip protector may be housed within the shank and is adapted to actuate between a retracted and an extended position. An actuator mechanism may be used to cause the tip protector to move to the extended position when the tip of the trocar member has entered the patient""s body cavity and before the piercing blade has been fully inserted into the body cavity to guard against accidental punctures. The trocar tip protector may include a bulbous head through which the piercing blade is adapted to pass, the bulbous head having an annular surface matable to an annular surface on the shank to form a smoothly tapered cone-shaped distal end of the trocar. A tip protector indicator may also be provided to provide a visual indication of whether the tip protector is in the retracted or extended position.